High hydrostatic pressure is being increasingly investigated in food processing. It causes
microbial inactivation and therefore extends the shelf life and enhances the safety of food
products. Yeasts, molds, and vegetative cells of bacteria can be inactivated by pressures in the
range of 200 to 700 MPa.
Microorganisms are more or less sensitive to pressure depending on several factors such as
type, strain and the phase or state of the cells. In general, Gram-positive organisms are usually
more resistant than Gram-negative. High pressure processing modifies the permeability of the
cell membrane, the ion exchange and causes changes in morphology and biochemical
reactions, protein denaturations and inhibition of genetic mechanisms.
High pressure has been used successfully to extend the shelf life of high-acid foods such as
refrigerated fruit juices, jellies and jams. There is now an increasing interest in the use of this
technology to extend the shelf life of low-acid foods such as different types of meat products.